Hyouka Episode 19: Does Anyone Have Any Idea?
Episode 19 of 22 of Hyouka, aired August 26, 2012, 27 minutes. Available with English subtitles and dub where released.
Episode summary
Hotaro tells Eru that he can come up with a plausible explanation for any situation she can think of, so when a seemingly mundane schoolwide announcement is made, she challenges him to figure out the reason behind the announcement.